Royal Physical Society. ^bl 



three rounded parts, currents of water are caused by the 

 rapid motion of these appendages ; I was however fortunate 

 enough to see them rest from their sports. In the body of 

 the embryo granules may be seen moving about when the 

 creature is active. Probably four or five weeks elapse from 

 the depositing of the ova to the release of the young ; this I 

 mention with great caution, as at all times there is difficulty 

 here, caused by weather and other things. I have known 

 them in-shore in the early part of February, and found a few 

 as late as Midsummer. Thus far have I traced them ; beyond 

 I could never get with all my care ; for the Leptoclinum soon 

 becomes putrid, and then farewell to my young broods. It 

 was only by watching for the ripest ova that I got so far as 

 I did. I drew very many blanks to one prize. I never saw 

 the young alive above twice, and then only in the nest, 

 although I have watched them from 1854 to 1858. This year I 

 have done literally nothing, but hope to see before long, should 

 we be favoured with more genial weather than of late. From 

 their pairing, both in confinement and in the sea, I observe 

 that one is always considerably larger than the other. I 

 therefore think that the sexes are separate ; the lady is the 

 largest, much more beautifully marked, and decked in brighter 

 array, — no doubt to render her more attractive in the eyes of 

 her more sober clad and diminutive lord. Probably this 

 difference in size, colour, <fcc, will account for the two species 

 which are said to inhabit our shores ; and after all, they may 

 prove to be only one. I do not think the difference in the 

 shape of the shells can be altogether depended on as a safe 

 guide, for I have obtained all the forms figured in the "British 

 Mollusca," from specimens gathered the same day, and within 

 a few feet of each other. On this head I will not insist. Before 

 I came here I never met with them in such numbers. I have, 

 however, now collected them at Land's End and at John 

 o'Groat's. 



As there appears to be obscurity connected with the history 

 of this interesting portion of our Mollusca, I send this as my 

 mite towards clearing away some of the mist; and as I have 

 attended to fish and mollusca nests more than those of birds, I 

 tell where they are to be found, that you may go a-hunting for 

 yourselves. Should I be so fortunate as to do ever so little 



